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An atom has 2 protons, 4 neutrons, and 2 electrons. What is the approximate atomic mass of this atom?
- A. 2
- B. 4
- C. 6
- D. 8
Correct Answer: D
Rationale: The atomic mass of an atom is the sum of the protons and neutrons in its nucleus. In this case, the atom has 2 protons and 4 neutrons, totaling 6 particles in the nucleus. Therefore, the approximate atomic mass of this atom is 6, making choice C incorrect. The number of electrons does not significantly contribute to the atomic mass, as they are much lighter and located in the electron cloud surrounding the nucleus. Choices A, B, and C are incorrect as they do not reflect the correct calculation of atomic mass based on protons and neutrons only.
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What type of molecules are enzymes?
- A. Water molecules
- B. Protein molecules
- C. Tripolar molecules
- D. Inorganic molecules
Correct Answer: B
Rationale: The correct answer is B: Protein molecules. Enzymes are biological catalysts made up of proteins. They function by facilitating and speeding up chemical reactions in living organisms. Therefore, enzymes are primarily composed of protein molecules, not water, tripolar, or inorganic molecules. Choice A (Water molecules), Choice C (Tripolar molecules), and Choice D (Inorganic molecules) are incorrect because enzymes are specifically classified as proteins due to their structure and function in biological systems.
Which of the following best describes one of the roles of RNA?
- A. Manufacturing the proteins needed from DNA
- B. Creating the bonds between the elements that make up DNA
- C. Sending messages about the correct sequence of proteins in DNA
- D. Forming the identifiable double helix shape of DNA
Correct Answer: C
Rationale: The correct answer is C. RNA serves as a messenger that carries instructions from DNA for protein synthesis. It does not manufacture proteins directly from DNA (choice A), create bonds within DNA (choice B), or form the double helix structure of DNA (choice D). Therefore, the primary role of RNA is to convey information about the correct sequence of proteins to be synthesized based on the DNA sequences it receives.
What is the cellular function of cilia and flagella?
- A. Cilia and flagella are responsible for cell movement.
- B. Cilia and flagella synthesize proteins.
- C. Cilia and flagella help protect the cell from its environment.
- D. Cilia and flagella have enzymes that help with digestion.
Correct Answer: A
Rationale: The correct answer is A: Cilia and flagella are responsible for cell movement. Cilia and flagella are specialized structures found on the surface of many types of cells. They are involved in the movement of the cell itself or in moving substances around the cell. This movement helps in various functions such as propulsion, moving fluids, and sensing the environment. Choices B, C, and D are incorrect. Cilia and flagella are not involved in synthesizing proteins, protecting the cell from its environment, or aiding in digestion. Their primary function is related to cell movement and cellular transport.
Which part of the cell serves as the control center for all cell activity?
- A. Nucleus
- B. Cell membrane
- C. Cytoplasm
- D. Mitochondria
Correct Answer: A
Rationale: The corrected question and answer are accurate. The correct answer is A: Nucleus. The nucleus is known as the control center of the cell as it contains the cell's genetic material (DNA) and directs all cell activities including growth, metabolism, and reproduction. The other organelles listed in the choices, while important for various cellular functions, do not serve as the central control center for overall cell activity.
Two nursing students will be completing a scientific experiment measuring the mass of chewed gum after one-minute chewing increments. Which lab equipment will the students most likely use?
- A. Triple beam balance
- B. Anemometer
- C. Hot plate
- D. Microscope
Correct Answer: A
Rationale: The correct answer is A: Triple beam balance. A triple beam balance is the most suitable lab equipment for measuring mass accurately, which is necessary for this experiment. An anemometer measures wind speed, a hot plate is used for heating substances, and a microscope is used for magnifying objects, none of which are relevant to measuring the mass of chewed gum.